Evolution on the mound: Why humans throw so well

Published 5:06 pm, Wednesday, June 26, 2013

But he could have, according to a group of scientists who offer new evidence that the classic overhand throw used by ballplayers, rock tossers and tomato hurlers is an evolutionary adaptation dependent on several changes in anatomy.

They first appeared, the researchers say, about 1.8 million years ago, when humans most likely began to hunt big game and needed to throw sharp objects hard and fast.

No other primate throws with anything comparable to human force. Chimpanzees are much stronger than humans, but the best an adult male can do is about 20 mph. A 12-year-old human can easily pitch three times that fast.

Clearly, the reason is not muscle strength, according to a report in the journal Nature released Wednesday. Using motion-capture video, Neil Roach and his colleagues at George Washington University analyzed the throwing motions of 20 college athletes.

Their conclusion: The shoulder must be storing energy when the ball is brought back before the throw - "just like a slingshot," Roach explained.

Several developments in anatomy allowed humans to throw this way, he said, including a waist that allows twisting and a relatively open shoulder.

But, if it is so natural, why do pitchers have so many shoulder problems?